In order to allow a machine such as a gas engine, elevator, or mining/construction machine to operate constantly, maintenance work on the machine is essential. One of effective techniques for maintenance work is the technique of gathering sensor data from sensors attached to each part of the machine, then carrying out abnormality diagnosis of the machine on the basis of the gathered sensor data, and carrying out causal analysis of an abnormality if it is found.
To carry out this technique, abnormality diagnosis of the sensor data of the machine is carried out, and if an abnormality is found, the sensor data is gathered at a data center via communication or the like, so as to carry out causal analysis. FIG. 1 is an example in which engine cooling water temperature and engine load factor combined with measurement time are gathered from machines. In the case of a machine operating at a site where communication often breaks down or where the communication speed drops, data is temporarily stored in a storage device installed in the machine, and the unsent sensor data is collectively sent when the communication state with the data center is good. If the already sent sensor data is erased from the storage device of the machine, the available capacity of the storage device can be saved as well.
However, if the drop in the communication speed continues for a long time, the amount of data that can be sent to the data center decreases. Therefore, the sensor data cannot erased from the storage device installed in the machine, posing the problem of running out of the available capacity.
As a data gathering method to solve such a problem, for example, PTL 1 discloses the invention of sending a warning to the data center if the remaining available capacity of the storage device installed in the machine has fallen to or below a threshold.